问题遇到的现象和发生背景
创建一个类Book，创建一个ArrayList，将多个book对象加入其中，实现在多个页面上（通过session）完成其数据的跨页面共享。
问题相关代码，请勿粘贴截图
%--
Document : array
Created on : 2022-5-30, 15:47:48
Author : Administrator
--%>
<%@page import="com.cn.book"%>
<%@page import="java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<%
ArrayList<book> booklist=new ArrayList<book>();
book book1=new book("0001","javaweb");
booklist.add(book1);
session.setAttribute("book1", booklist);
response.sendRedirect("out.jsp");
%>
</body>
</html>
<%@page import="com.cn.book"%>
<%@page import="java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<%
@SuppressWarnings("unchecked")
ArrayList <book> booklist=(ArrayList<book>) session.getAttribute("book");
if(booklist.size()>0){
for(book book1:booklist)
{
out.print("id"+book1.getId()+"< >"+"bookname"+book1.getName());
}
}
%>
</body>
</html>
运行结果及报错内容
